Boiler plug



Jan. 18, 1927. 1.614.154

F. K. MURPHY ET AL BOILER PLUG Filed May 5, 1924 A L/ I;

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Patented Jan. 18, 1927.

. UNITED STATES PATENT OFFICE.

FRED K. MURPHY, DANIEL J. MULLEN, AND RAYMOND W. RETTEREB, OF.INDIANAPOLIS, INDIANA.

BOILER PLUG.

Application filed May 3, 1924. Serial No. 710,856.

This invention pertains to a clean-out for boilers and the like.

Whereas the usual clean-out plug used on boilers is adapted to screwtightly therein, the threads become corroded and rusted making itdifficult to unscrew the plug, or replace it. Furthermore the screwthreads in the boiler become worn and broken so that eventually it isnecessary to retap the boiler and use a larger plug.

It is the object of this invention to provide a plug having a removablecore so that the plug can remain screwed into the boiler permanently,access to the interior of 5 the boiler being had through an opening inthe plug which is closed by a core held in place by suitable screwthread segments with plug respect to the plug, said screw threads beingprotected from corrosion by the water by a ground ball joint and beveledseat.

Other features of the invention with respect to the locking and wedgingconstruction as well as a means for preventing the movement of the corefrom the closed position will be herein after more fully set forth anddescribed. I

The value of this invention resides in the fact that it eliminates thedanger of a plug blowing out causing damage and often per- 140 sonalinjury. This has been occasioned heretofore, where in screwing the plugin place after having been removed, the threads are crossed, causingsome threads to be stripped so as to weaken them and permit the highpressure of the boiler to cause the blowout with the consequent dangerand damage. This invention eliminates that danger by reason of the factthat the screw threaded plug remains permanently in the boiler, accessbeing had only through the removable core.

The full nature of the invention will be understood from theaccompanying drawings and the following description and claims.

Fig. 1 is a plan view of theplug with the core in unlocked position.Fig.2 is the same as Fig. 1, showing the plug with the core in lockedposition thereon and provided with a retaining key. 'Fig. 3 is a sectiontaken on the line 33 of Fig. 2. Fig. 4 is aside elevation of the closingcore. Fig. 5 is a central vertical section through the plug taken on theline 55 of Fig. 1 with the core removed.

In the drawing there is shown a plug for a boiler or the like having athreaded portion 10 adapted to screw into a tapped opening in theboiler, said threaded portion being surmounted with an annular outwardlyextending head 11. The plug is in the form of a shell having arelatively large opening 12 which is adapted to be closed by the core13. Adjacent said opening and contained within the head 11 there isprovided a beveled seat 14 adapted to receive a correspondingly ballportion 15 on the cap so as to permit a ground fit to be hadtherebetween.

The head of the plug is provided with oppositely disposed and inwardlyextending thread segments 16, each of which extends a quarter of thedistance about the innerperipheryof the head. Said thread seg ments aretapered as best shown in Fig. 5, to give a substantial pitch. As shownherein, they are formed with a half inch pitch.

The core is provided with corresponding outwardly extending threadsegments 17 formed about the periphery thereof and diametrically opposedto each other. Said thread segments 17 likewise extend a quarterdistance about the periphery, and lie adjacent the bevel sealing portion14, the same having anopposite and corresponding pitch as shown in Fig.4. This arrangement is such that the core may be inserted in the head ofthe plug so as to be seated upon the beveled portion 14 thereof, thethread segments 17 dropping intoposition between the ends of the threadsegments 16 on the plug. Therefore, upon turning the core within theplug head the segments 17 and 16 will interlock as shown in Figs. 1 and2, and by reason of their respective pitches will screw together so thatthe tighter the cap is turned 95 the more firmly they will be screwedinto position, causing the ground bevel portion 14. and ball 15 to bemore firmly and securely sealed to withstand leakage and pressure.

The core is further provided with a head 18 having a centrally disposedhexagonal recess 19 for receiving a suitable wrench. It will be obvioustherefore that on applying the wrench thereto and turning the core aquarter turn in one direction it will be interlocked in the plug so asto close the opening' therein, and the greater the pressure exerted inturning the core the more firmly it will become seated for withstandingleakage.

On the other hand by turning the core a quarter turn in the oppositedirection it will become freed and can be readily removed from the plugso that access may be had to the interior of the boiler.

A suitable means may be employed" for limiting the turning movement ofthe core in closing position, which is herein shown as comprising the.pin which extends through the ends of the segments 16 away from thereceiving. ends thereof so that it will be impossible to turn'the corebeyond the locking engagement of screw threads. l'lowever the threadsegments are so'formed' as to cause them to screw together when the capis nartially turned to locking engagement so that there will besufficient latitude permitted'for further turning it to compensate forwear. f

For retaining the .core in locked position, or rather for preventing it.from being turned so as to be released from the plug, there is provideda tapered locking key pin 21 having a head 22 adapted to be insertedthrough a taperedtangential opening 23 in the head 11. After the core isturned into locking engagementwith the head the pin maybe freely passedthrough said opening and locked therein by the end piece 24, which fallsinto locking position by gravity because of its elf center pivotedconnection 25.

- iVith respect'to the locking pin, it will be observed that it is sopositioned with respect .to the core as to permit the core to betightened but prevent its becoming loosened.

The invention claimed is: V 1. A plug for boilers or the like having anopening therethrough, a bevel seat adjacent said opening, a core havinga ball portion adapted to rest on sald seatand havmga ground -,tit vtherewith, inwardly formed -,grooves having their open ends spaced apart"within said plugexternally of said opening and increasing in thicknessfrom one end to the other so as to have a suitable pitch, andcorresponding oppositely disposed thread segments formed onsaid coreexternally of.

said ball portion and tapering in thickness from one end to the other soas to havc a corresponding pitch, said segments being so arranged thatsaid core maybe inserted {in said plug for closing said 1 opening andturned therein so thatthe segments will engage'and wedge 1n saidgroovesinto locking position.

- 2. A plug construction, comprising a tubul'ar. body having one endsuitably formed -for boiler mounting .and a central opening.

therethrough, a laterally directed flange opposite the mountable end ofthe body and including a circular valve seat at the junction thereof, aplurality of inwardly and radially extending overhanging portionsintegral with thefiange and circularlyconnectedi together for forming:protected and enclosed segmental thread grooves with theflange face,each of said overhanging portions having an inclined face and arrangedin spaced relation with each other, and a cap having acircular valveforming portionat the bottom thereof, a tool engageable portion at thetop thereof, and a plurality of outwardly and radially extending threadforming segments in spaced relation with each other and intermediate thetop and bottom, each thread forming segment having an outer inclinedface for wedging engagement with the inclined face of the groove, saidoverhanging portions being spaced apart sufficient to permitlongitudinal axial seating of the thread forming segments and valveseating prior to rotational locking. i

3. A ,device of the character defined by claim 2, characterized by thesealing cap being so arranged that no portion of it projects laterallyor longitudinally beyond the plug body when seated.

defined by claim 2, characterizedby the valve and valve seat beingcomplementarily formed, one. being a bevelled surface and the other aball surface.

5. A plug for boilers or the like having an opening therethrough, abevelseat externally ofand adjacent said opening, a core having a ballportion adapted to restin said seat and having. a ground fit therewith,inwardly formed groovcsin said plug externally of said 1 opening I widthfrom one end to the other so as to have a suitable pitch, correspondingand oppositely disposed thread segments formed vonsaid. core tapering inthickness from one end to the other so as to have a correspondingpitch,said segments being so arranged that saidcore may be insertedin saidplugfor closing said opening and turned thereinso as to engage withinsaid grooves and wedge into locking posi tion, a key men'iberadaptedtobe engaged in said plug upon said core being locked in position thereinso .as to prevent it being turned to unlocking position, and a lugpivotally mounted off centeron one end of Said member soas toibe capableof dropping cluding a substantially tangentially arranged recesscommunicating with the locking groove, and the addition of a keyreceivable'by said groove and tangentiallyengaging said cap forpreventing the unthread- .ingmovementofthesame.

8. A plug construction, comprising-atria bular body having an exterorally threaded portion at one end, a lateral enlargement at theopposite end including a circular valve seat concentric with the tubularbody at the junction therewith, and a plurality of overhanging inwardlyand radially extending spaced portions circularly connected together,each of said portions forming with the face of the lateral enlargement aplurality of arcuate and protected grooves, each of said arcuate grooveshaving pairs of walls relatively inclined to each other, and a caphaving its top formed for tubular engagement and its bottom providedwith a circular valve for seating engagement with the valve seat, saidvalve and valve seat being cooperatively formed to rovide a fluid andpressure tight joint, an a similar number of similarly spaced radiallyextending thread forming sections on the cap each having a pair ofrelatively inclined faces whereby partial relative rotation between thecap and body wedgingly secures the cap and body together in fluid andpressure tight relation. In witness whereof, we have hereunto affixedour signatures. Y

FRED K. MURPHY.

DANIEL J. MULLEN.

RAYMOND W. RETTERER.

